3) How play the glissandi.

4) The last section, looking for utopia, video by Christophe Roy.

III-/ Guide for performers

A/ Comparative analysis of existing versions

1) Two generations of performers

To start this guide I propose a comparative analysis between the different recordings that exist to my knowledge: Siegfried PALM, Rohan de SARAM, Pierre STRAUCH, Christophe ROY and Arne DEFORCE. If we compare the duration of each versions, two generations can be distinguished :

First generation:

Siegfried Palm : 14'39” (1974)

Rohan de Saram : 15'20” (1992)

Pierre Strauch : 12'40” (1992)

Second generation:

Christophe Roy : 18'50” (2000)

Arne Deforce : 19'05” (2011)

2) The tempo question

The main problem in the Nomos Alpha performance is the tempo. That's why there are such differences between each version. The tempi written by Xenakis are very fast, and it's clearly impossible to play all notes in Xenakis' tempo, the piece is too virtuoso. In this tempo, many details are lost, and it's very difficult to control the intonation. Therefore, the cellists have to make a choice, which isn’t just about tempo.

The first generation chose to play close to Xenakis’ indicated tempo. For them, the main priorities are to keep the tempo and the coherence of the tempo in the whole piece.
The second generation played slower, their priorities in the piece being the sonorities, the energy, the precision of the intonation, and the many details written by Xenakis - they played all notes written by Xenakis. But in these versions, the tempo is slowed down, and there is no tempo coherence during the whole piece. For example, two basic sounds could be play in two different tempo as we will see in the video 1, choose your tempo in Nomos Alpha.

Which way would be the best ?
I prefer the choice of the second generation for several reasons, theses information are develop in the video 1:

1. The intonation: as we saw in the chapter on the "sieves", the precision of the intonation is an important part of Xenakis' composition process in this period.

2. The sonorities: the sonorities, the mass of sound, global perception of the sound: these concepts are the main aspects of Xenakis music. I think that when we practice and perform Nomos Alpha, sound research should be at the center of our attention.

3.  

   The rhythm : I recall that Nomos Alpha is written with an “extra-temporal architecture”, as xenakis wrote in the preface of the score,  meaning it's an outside-of-time music. Xenakis does not use rhythm as a counterpoint element or polyrhythm, there is no hierarchy in a bar. That means there is no rhythmic organisation in carrure like in serial music or more generally in the intime-music. Here again, rhythmic writing participates in the creation of sound masses.

4. Last but not least, Xenakis himself was probably fully aware of this impossibility. Indeed, when we calculate how long the piece should last, we find 10'26”. But on the score Xenakis wrote the piece as lasting 15'. In addition, when Christophe Roy played the piece for Xenakis, the composer approved this slower tempo.
   

B/ Tutorial videos

In these videos, with Christophe Roy we are going to explain how practice some important aspects of Nomos Alpha.

1) Choose your tempo in Nomos Alpha.

I want to thank:

• Christophe Roy for his avaibility and talent !
• Pauline Berthelemy and Simon Buvat for reccording of the video with Christophe Roy.

2) Doubles stops, different intensities on each string, video by Christophe Roy.

To the conclusion

I very glad to present you this video. Christophe Roy he is the first and the only one to have found this fingering of the last section of Nomos Alpha. As a result, he is the only one to play this last section with only one cello. All other cellists play this section with a second cellist in backstage  who plays one of the two lines.

Score of the given example in the video: beginning of the piece.

Score of the given example in the video: middle of the page 7